Method and apparatus for feeding back information about channel between antenna arrays

ABSTRACT

A method for feeding back information about a channel between antenna arrays is provided, which includes: receiving, by a first network device, sub-channel channel information of N×M sub-channels that is sent by a second network device, where an antenna array of the first network device includes M panels, an antenna array of the second network device includes N panels, the channel between the first network device and the second network device includes the N×M sub-channels, M is a positive integer that is greater than or equal to 2, N is and N is a positive integer, M and N are not to be 1 at the same time, and the M panels and the N panels each includes at least two antennas; generating channel information of the channel between the first network device and the second network device according to the sub-channel channel information of the N×M sub-channels.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/816,617, filed on Nov. 17, 2017, which is a continuation ofInternational Application No. PCT/CN2015/079290, filed on May 19, 2015,all of which are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

Embodiments of the present disclosure relate to the communicationsfield, and more specifically, to a method and an apparatus for feedingback information about a channel between antenna arrays.

BACKGROUND

In a Long Term Evolution (Long Term Evolution, LTE) system and itssubsequent evolution, a quantity of antennas at a data transmit endincreases rapidly, and a quantity of user equipments (UEs) that need tobe served also increases rapidly. An increase in the quantity ofantennas can provide a higher spatial degree of freedom, therebycreating an advantageous condition for multiplexing multiple datastreams in downlink space (for example, single user multiple-inputmultiple-output (SU-MIMO) or multi-user multiple-input multiple-output(MU-MIMO)). Downlink channel state information (CSI) measurement isclassified into two types: obtaining instantaneous CSI, for example, achannel; and obtaining statistical CSI, for example, a channelautocorrelation matrix. A function of a massive MIMO system lies more instatistically performing channel processing, including dimensionreduction and grid of beam (GOB).

SUMMARY

Embodiments of the present disclosure provide a method and an apparatusfor feeding back information about a channel between antenna arrays, soas to reduce complexity of obtaining channel information of a channelbetween antenna arrays of different network devices.

According to a first aspect, an example of the present disclosureprovides a method for feeding back information about a channel betweenantenna arrays, including:

-   -   receiving, by a first network device, channel information of the        N×M sub-channels that is sent by a second network device, where        an antenna array of the first network device includes M        subarrays, an antenna array of the second network device        includes N subarrays, a channel between the antenna array of the        first network device and the antenna array of the second network        device includes the N×M sub-channels, M and N are positive        integers and are not both 1, and the M subarrays and the N        subarrays each include at least two antennas; and    -   generating channel information of the channel between the        antenna array of the first network device and the antenna array        of the second network device according to the channel        information of the N×M sub-channels that is from the second        network device.

In a first possible implementation of the first aspect, the channelinformation of the N×M sub-channels includes a rank indicator RI and aprecoding matrix indicator PMI, each of the N×M sub-channels correspondsto one sub-channel matrix, and the channel information of the N×Msub-channels is obtained according to the following steps:

-   -   obtaining autocorrelation matrices of sub-channel matrices        corresponding to the N×M sub-channels; and    -   obtaining the RI and the PMI of the N×M sub-channels according        to the autocorrelation matrices of the channel matrices of the        N×M sub-channels.

In a second possible implementation of the first aspect, the channelinformation of the N×M sub-channels includes precoding, each of the N×Msub-channels corresponds to one sub-channel matrix, and the channelinformation of the N×M sub-channels is obtained according to thefollowing steps:

-   -   obtaining autocorrelation matrices of sub-channel matrices        corresponding to the N×M sub-channels; and    -   obtaining the precoding of the N×M sub-channels according to the        autocorrelation matrices of the channel matrices of the N×M        sub-channels.

In a third possible implementation of the first aspect, the method forfeeding back information about a channel between antenna arrays furtherincludes:

-   -   sending, by the first network device, subarray configuration        information to the second network device, where the subarray        configuration information is used to divide the antenna array of        the first network device into the M subarrays, and M is a        positive integer greater than or equal to 2.

With reference to the third possible implementation of the first aspect,in a fourth possible implementation of the first aspect, the subarrayconfiguration information includes at least one pattern, and the Msubarrays are determined according to the at least one pattern.

With reference to the third possible implementation of the first aspect,in a fifth possible implementation of the first aspect, the subarrayconfiguration information includes a start port number of each subarray,and each of the M subarrays is determined according to the start portnumber.

With reference to the third possible implementation of the first aspect,in a sixth possible implementation of the first aspect, the subarrayconfiguration information is sent by using a physical downlink controlchannel PDCCH, Radio Link Control RLC signaling, or a physical broadcastchannel PBCH.

According to a second aspect, an example of the present disclosureprovides another method for feeding back information about a channelbetween antenna arrays, including:

-   -   generating, by a second network device, channel information of        N×M sub-channels of a channel between an antenna array of a        first network device and an antenna array of the second network        device, where the antenna array of the first network device        includes M subarrays, the antenna array of the second network        device includes N subarrays, M and N are positive integers and        are not both 1, and the M subarrays and the N subarrays each        include at least two antennas; and    -   sending the channel information of the N×M sub-channels to the        first network device, so that the first network device generates        channel information of the channel between the antenna array of        the first network device and the antenna array of the second        network device according to the channel information of the N×M        sub-channels.

In a first possible implementation of the second aspect, the channelinformation includes a rank indicator RI and a precoding matrixindicator PMI, each of the N×M sub-channels corresponds to onesub-channel matrix, and the channel information of the N×M sub-channelsis obtained according to the following steps:

-   -   obtaining autocorrelation matrices of channel matrices of the        N×M sub-channels; and    -   obtaining the RI and the PMI of the N×M sub-channels according        to the autocorrelation matrices of the channel matrices of the        N×M sub-channels.

In a second possible implementation of the second aspect, the channelinformation of the N×M sub-channels includes precoding, each of the N×Msub-channels corresponds to one sub-channel matrix, and the generating,by a second network device, channel information of N×M sub-channels of achannel between an antenna array of a first network device and anantenna array of the second network device specifically includes:

-   -   obtaining autocorrelation matrices of channel matrices of the        N×M sub-channels; and    -   obtaining the precoding of the N×M sub-channels according to the        autocorrelation matrices of the channel matrices of the N×M        sub-channels.

In a third possible implementation of the second aspect, the methodfurther includes:

-   -   receiving, by the second network device, subarray configuration        information sent by the first network device, where the subarray        configuration information is used to divide the antenna array of        the first network device into the M subarrays, and M is a        positive integer greater than 2.

With reference to the third possible implementation of the secondaspect, in a fourth possible implementation of the second aspect, thesubarray configuration information includes at least one pattern, andthe N subarrays are determined according to the at least one pattern.

With reference to the third possible implementation of the secondaspect, in a fifth possible implementation of the second aspect, thesubarray configuration information includes a start port number of eachsubarray, and the M subarrays are determined according to the start portnumber of each subarray.

With reference to the third possible implementation of the secondaspect, in a sixth possible implementation of the second aspect, thesubarray configuration information is sent by using a physical downlinkcontrol channel PDCCH, Radio Link Control RLC signaling, or a physicalbroadcast channel PBCH.

According to a third aspect, an example of the present disclosureprovides an apparatus for feeding back information about a channelbetween antenna arrays, including:

-   -   a receiving module, configured to receive channel information of        the N×M sub-channels that is sent by the second network device,        where an antenna array of the first network device includes M        subarrays, an antenna array of the second network device        includes N subarrays, a channel between the antenna array of the        first network device and the antenna array of the second network        device includes the N×M sub-channels, M and N are positive        integers and are not both 1, and the M subarrays and the N        subarrays each include at least two antennas; and    -   a processing module, configured to generate channel information        of the channel between the antenna array of the first network        device and the antenna array of the second network device        according to the channel information of the N×M sub-channels        that is from the receiving module.

In a first possible implementation of the third aspect, the sendingmodule is configured to send subarray configuration information to thesecond network device, the subarray configuration information is used todivide the antenna array of the first network device into the Msubarrays, and M is a positive integer greater than or equal to 2.

With reference to the first possible implementation of the third aspect,in a second possible implementation of the third aspect, the subarrayconfiguration information includes at least one pattern, and the Msubarrays are determined according to the at least one pattern.

With reference to the first possible implementation of the third aspect,in a third possible implementation of the third aspect, the subarrayconfiguration information includes a start port number of each subarray,and the M subarrays are determined according to the start port number ofeach subarray.

With reference to the first possible implementation of the third aspect,in a fourth possible implementation of the third aspect, the subarrayconfiguration information is sent by using a physical downlink controlchannel PDCCH, Radio Link Control RLC signaling, or a physical broadcastchannel PBCH.

According to a fourth aspect, an example of the present disclosureprovides an apparatus for feeding back information about a channelbetween antenna arrays, where the channel information feedback apparatusincludes:

-   -   a processing module, configured to generate channel information        of N×M sub-channels of a channel between an antenna array of a        first network device and an antenna array of the second network        device, where the antenna array of the first network device        includes M subarrays, the antenna array of the second network        device includes N subarrays, M and N are positive integers and        are not both 1, and the M subarrays and the N subarrays each        include at least two antennas; and    -   a sending module, configured to send the channel information of        the N×M sub-channels to the first network device, so that the        first network device generates channel information of the        channel between the antenna array of the first network device        and the antenna array of the second network device according to        the channel information of the N×M sub-channels.

In a first possible implementation of the fourth aspect, the channelinformation includes a rank indicator RI and a precoding matrixindicator PMI, each of the N×M sub-channels corresponds to onesub-channel matrix, and the processing module is specifically configuredto:

-   -   obtain autocorrelation matrices of channel matrices of the N×M        sub-channels; and    -   obtain the RI and the PMI of the N×M sub-channels according to        the autocorrelation matrices of the channel matrices of the N×M        sub-channels.

In a second possible implementation of the fourth aspect, the channelinformation of the N×M sub-channels includes a rank indicator RI and aprecoding matrix indicator PMI, each of the N×M sub-channels correspondsto one sub-channel matrix, and the processing module is specificallyconfigured to:

-   -   obtain autocorrelation matrices of channel matrices of the N×M        sub-channels; and    -   obtain the RI and the PMI of the N×M sub-channels according to        the autocorrelation matrices of the channel matrices of the N×M        sub-channels.

In a third possible implementation of the fourth aspect, the apparatusfor feeding back information about a channel between antenna arraysfurther includes:

-   -   a receiving module, configured to receive subarray configuration        information sent by the first network device, where the subarray        configuration information is used to divide the antenna array of        the first network device into the M subarrays, and M is a        positive integer greater than or equal to 2.

With reference to the third possible implementation of the fourthaspect, in a fourth possible implementation of the fourth aspect, thesubarray configuration information includes at least one pattern, andthe N subarrays are determined according to the at least one pattern.

With reference to the third possible implementation of the fourthaspect, in a fifth possible implementation of the fourth aspect, thesubarray configuration information includes a start port number of eachsubarray, and the M subarrays are determined according to the start portnumber of each subarray.

With reference to the third possible implementation of the fourthaspect, in a sixth possible implementation of the fourth aspect, thesubarray configuration information is sent by using a physical downlinkcontrol channel PDCCH, Radio Link Control RLC signaling, or a physicalbroadcast channel PBCH.

BRIEF DESCRIPTION OF DRAWINGS

To describe the technical solutions in the examples of the presentdisclosure more clearly, the following briefly describes theaccompanying drawings required for describing the examples. Apparently,the accompanying drawings in the following description show merely someexamples of the present disclosure, and a person of ordinary skill inthe art may still derive other drawings from these accompanying drawingswithout creative efforts.

FIG. 1 is a schematic flowchart of a method for feeding back informationabout a channel between antenna arrays according to an example of thepresent disclosure;

FIG. 2 is a schematic diagram of antenna array division according to theexample shown in FIG. 1 of the present disclosure;

FIG. 3 is a schematic flowchart of a method for feeding back informationabout a channel between antenna arrays according to another example ofthe present disclosure;

FIG. 4 is a schematic diagram of an apparatus for feeding backinformation about a channel between antenna arrays according to anexample of the present disclosure; and

FIG. 5 is a schematic diagram of an apparatus for feeding backinformation about a channel between antenna arrays according to anotherexample of the present disclosure.

DETAILED DESCRIPTION

Sometimes, when a massive antenna system performs channel measurement,CSI obtaining mainly relies on downlink measurement and user equipment(UE) feedback. UE obtains space precoding according to downlink channelinformation, quantizes the space precoding according to a presetprecoding codebook, and then feeds back quantized space precoding to abase station. In an existing system, a quantity of antennas isrelatively small, and complexity of obtaining space precoding isacceptable. However, in an MU-MIMO scenario, there are tens of or evenmore antennas. Because obtaining precoding requires eigenvaluedecomposition on a channel matrix or on a channel autocorrelationmatrix, complexity of obtaining space precoding is excessively high,leading to excessively high complexity of obtaining channel information.Therefore, how to reduce the complexity of obtaining channel informationbecomes a problem that urgently needs to be resolved.

In the examples of the present disclosure, an antenna array of a firstnetwork device and an antenna array of a second network device aredivided into multiple antenna subarrays, channel information of multiplesub-channels that correspond to the multiple antenna subarrays and thatare between the antenna array of the first network device and theantenna array of the second network device is obtained, and channelinformation of a channel between the antenna array of the first networkdevice and the antenna array of the second network device is obtainedaccording to the channel information of the multiple sub-channels. Inthis way, complexity of obtaining channel information is reduced, andefficiency of channel information feedback is improved.

The following describes the technical solutions in the examples of thepresent disclosure with reference to the accompanying drawings in theexamples of the present disclosure. Apparently, the described examplesare some but not all of the examples of the present disclosure. Allother examples obtained by a person of ordinary skill in the art basedon the examples of the present disclosure without creative efforts shallfall within the protection scope of the present disclosure.

To facilitate understanding of the technical solutions in the examplesof the present disclosure, first, several related concepts areintroduced herein.

(1) Antenna

An antenna is an electronic device configured to transmit or receive aradio wave or an electromagnetic wave. Physically, an antenna is aconductor or a combination of multiple conductors. From the antenna, aradiating electromagnetic field can be generated due to appliedalternating voltage and associated alternating current. Alternatively,the antenna may be placed between electromagnetic waves. In this case,because of field induction, alternating current is generated inside theantenna, and alternating voltage is generated at a terminal of theantenna. A bandwidth of an antenna means a frequency range in which theantenna works effectively.

(2) Antenna Array

Directivity of a single antenna is limited. For application in variousscenarios, two or more single antennas that work at a same frequency arefed with electricity and arranged spatially according to a specificrequirement, thereby constituting an antenna array, also referred to asan antenna array. Antenna radiation units that constitute the antennaarray are referred to as array elements.

A working principle of the antenna array may be regarded assuperposition of electromagnetic waves. When several electromagneticwaves are transmitted to one area, vector superposition occurs on theelectromagnetic waves according to a superposition principle. Asuperposition result not only relates to an amplitude of each of theelectromagnetic waves, but also relates to a phase difference betweenthe electromagnetic waves in an encounter section. A space phasedifference is caused when electromagnetic waves transmitted by transmitantennas in different positions are delivered to one receiving area.Therefore, the following two situations are bound to occur on severalelectromagnetic waves in an encounter area: in-phase superposition,causing an increase in total field strength; out-of-phase superposition,causing a decrease in total field strength. If increase and decreaseareas of the total field strength remain relatively unchanged in space,this is equivalent to changing a radiation field structure of a singleantenna by using an antenna array. This is the principle of how theantenna array changes a size and directivity of a radiation field.

Currently, channel state information (CSI) measurement may bemeasurement of instantaneous CSI, for example, measurement of a channelitself, or may be measurement of statistical CSI, for example,measurement of a channel autocorrelation matrix. For a massive antennaarray, the meaning of measurement lies more in statistically processingthe channel, including dimension reduction and grid of beam (GOB).

Typically, when the massive antenna array performs transmissionaccording to a frequency division duplex (FDD) standard or a timedivision duplex (TDD) standard, CSI is obtained mainly by means ofdownlink measurement and user equipment (User equipment, UE) feedback.Specifically, in Long Term Evolution (LTE)/LTE-A, UE obtains a rankindicator (Rank indicator, RI) and a precoding matrix indicator (PMI)according to channel information obtained by means of downlinkmeasurement, quantizes the RI and the PMI according to a presetprecoding codebook, and then feeds back quantized RI and PMI to a basestation, so as to determine a precoding matrix. After receiving the RIand the PMI, the base station sends data and a cell-specific referencesignal (CRS) used for demodulation or a demodulation reference symbol(DM-RS).

A first example of the present disclosure provides a channel informationfeedback method for an antenna array, so as to obtain channelinformation of a channel between an antenna array of a first networkdevice and an antenna array of a second network device.

The first network device may be a network device in one of the followingforms: a macro base station, a micro base station, user equipment, andthe like. The antenna array of the first network device includes Msubarrays. The second network device may be user equipment, for example,a portable device such as a mobile telephone or a tablet computer. Withdevelopment of the Internet of Things in the future, the second networkdevice may alternatively be a terminal with an antenna, for example, asmart appliance such as a smart refrigerator or a smart television.

Referring to FIG. 1, an implementation process of the method for feedingback information about a channel between antenna arrays in this exampleof the present disclosure includes the following steps.

101: The second network device generates channel information of N×Msub-channels between the antenna array of the first network device andthe antenna array of the second network device.

The antenna array of the first network device includes M subarrays, andthe antenna array of the second network device includes N subarrays. Mand N are positive integers and are not both 1. The M subarrays and theN subarrays each include at least two antennas. All antenna subarrays ina typical antenna array include same quantities of antennas and aresymmetrically deployed. The antenna array of the first network device isused as an example for description. Referring to FIG. 2, assuming thatthe antenna array includes 36 antennas and the antenna array of thefirst network device is divided into four subarrays, each subarrayincludes eight antennas, and the four subarrays are symmetricallydeployed. It can be understood that a configuration rule is not limitedthereto. In another example, subarrays may include different quantitiesof antennas and may be deployed asymmetrically.

Corresponding to M sub-channels of the first network device and Nsub-channels of the second network device, there are N×M sub-channelsbetween the antenna array of the first network device and the antennaarray of the second network device.

Specifically, the channel information of the N×M sub-channels betweenthe antenna array of the first network device and the antenna array ofthe second network device includes a rank indicator RI and a precodingmatrix indicator PMI or includes precoding. The second network devicecan obtain the channel information of the N×M sub-channels in responseto a reference signal (RS) from the first network device, or can obtain,based on channel reciprocity, the channel information of the N×Msub-channels.

In this example, it is assumed that K=N×M. The channel information ofthe K sub-channels is obtained according to the following steps:

-   -   obtaining autocorrelation matrices of channel matrices of the K        sub-channels, where for example, according to preset subarray        configuration information, the channel between the first network        device and the second network device is divided into the K        sub-channels:

H=(H ₁ ,H ₂ , . . . ,H _(k) , . . . H _(K)),

-   -   where a dimension of H_(k) is L×M_(k),

${{\sum\limits_{k}M_{k}} = M},$

and M_(k) is a quantity of antenna ports in the k^(th) antenna group;and

-   -   obtaining RI_(k) and PMI_(k) of the K sub-channels according to        the autocorrelation matrices of the channel matrices of the K        sub-channels. For example, steps of obtaining the RI and the PMI        of the K sub-channels include:    -   obtaining, by the second network device, autocorrelation        matrices of the K sub-channels according to the K sub-channels;        and    -   performing eigenvalue decomposition (EVD) or singular value        decomposition (SVD) on the autocorrelation matrices        corresponding to the K sub-channels, to obtain corresponding        precoding U_(k).

The second network device can feed back the precoding U_(k)corresponding to the K sub-channels to the first network device; orquantize a codebook corresponding to the U_(k) to obtain RI_(k) andPMI_(k) of the K sub-channels, and feed back the RI_(k) and the PMI_(k)to the first network device. Specifically, a dimension of each codewordin a precoding codebook used by the first network device and the secondnetwork device is M_(k)×r, where M_(k) is a quantity of antenna ports inthe k^(th) antenna group, and r is a quantity of flows.

It can be learnt that, when the first network device has a relativelylarge quantity of antennas, complexity of the SVD or EVD is relativelyhigh. Dividing the antenna array of the first network device and theantenna array of the second network device into groups can significantlyreduce the complexity of the SVD or EVD.

102: The second network device sends, to the first network device, thechannel information of the N×M sub-channels between the antenna array ofthe first network device and the antenna array of the second networkdevice.

103: The first network device receives, from the second network device,the channel information of the N×M sub-channels between the antennaarray of the first network device and the antenna array of the secondnetwork device.

104: The first network device generates the channel information of thechannel between the antenna array of the first network device and theantenna array of the second network device according to the channelinformation, from the second network device, of the N×M sub-channelsbetween the antenna array of the first network device and the antennaarray of the second network device. Optionally, when the channelinformation, received by the first network device, of the N×Msub-channels is the precoding U_(k), the first network device obtainsprecoding U of the channel between the antenna array of the firstnetwork device and the antenna array of the second network deviceaccording to the precoding U_(k) of the K sub-channels. Specifically, Uis obtained according to the following expression:

$U = \begin{bmatrix}U_{1} & \; & \; & \; \\\; & U_{2} & \; & \; \\\; & \; & \ddots & \; \\\; & \; & \; & U_{K}\end{bmatrix}$

The first network device quantizes the precoding U to obtain RI and PMIof the channel between the antenna array of the first network device andthe antenna array of the second network device. When the channelinformation, received by the first network device, of the N×Msub-channels is the rank indicator RI_(k) and the precoding matrixindicator PMI_(k), the RI and the PMI of the channel between the antennaarray of the first network device and the antenna array of the secondnetwork device are obtained by combining the rank indicator RI_(k) andthe precoding matrix indicator PMI_(k) of the K sub-channels or by meansof a capacity maximization algorithm or another algorithm.

Referring to FIG. 3, in another example, optionally, the method forfeeding back information about a channel between antenna arrays furtherincludes:

100: The first network device sends subarray configuration informationto the second network device, where the subarray configurationinformation is used to divide the antenna array of the first networkdevice into the M subarrays, and M is a positive integer greater than 2.

Optionally, step 100 is performed before step 101, and the subarrayconfiguration information is used to preset the antenna array of thefirst network device.

Optionally, step 100 is performed after step 103, and the subarrayconfiguration information is used to dynamically update the antennaarray of the first network device. Specifically, when division of theantenna array of the first network device changes, the first networkdevice sends the subarray configuration information to the secondnetwork device. The subarray configuration information can be sent byusing a physical downlink control channel (PDCCH), Radio Link Control(RLC) signaling, or a physical broadcast channel (PBCH).

Regardless of whether the subarray configuration information is used topreset the antenna array of the first network device or to dynamicallyupdate the antenna array of the first network device, the subarrayconfiguration information includes a subarray division rule. The antennaarray of the first network device is divided according to the presetrule included in the subarray configuration information. Optionally, inanother example, the preset rule is numbered, so that the first networkdevice informs the second network device of the used preset rule bysending the number.

For example, the preset rule includes at least one pattern, and the Nsubarrays of the antenna array of the second network device aredetermined according to the at least one pattern. Referring to FIG. 2,as an example of a pattern, the antenna array of the first networkdevice is divided into four subarrays.

For example, the preset rule is a start port number of each subarray,and each of the N subarrays of the antenna array of the first networkdevice is determined according to the start port number.

In this example, an antenna array of a first network device and anantenna array of a second network device are divided into multipleantenna subarrays, channel information of multiple sub-channels thatcorrespond to the multiple antenna subarrays and that are between theantenna array of the first network device and the antenna array of thesecond network device is obtained, and channel information of a channelbetween the antenna array of the first network device and the antennaarray of the second network device is obtained according to the channelinformation of the multiple sub-channels. In this way, complexity ofobtaining channel information is reduced, and system efficiency isimproved.

Another example of the present disclosure provides an apparatus forfeeding back information about a channel between antenna arrays. Theapparatus is applied to a first network device and is configured toperform step 103 and step 104. Referring to FIG. 4, an apparatus 200 forfeeding back information about a channel between antenna arrays includesa receiving module 210 and a processing module 220.

The receiving module 210 is configured to receive channel information ofN×M sub-channels that is sent by a second network device. An antennaarray of the first network device includes M subarrays. An antenna arrayof the second network device includes N subarrays. A channel between theantenna array of the first network device and the antenna array of thesecond network device includes the N×M sub-channels. M and N arepositive integers and are not both 1. The M subarrays and the Nsubarrays each include at least two antennas.

The processing module 220 is configured to generate channel informationof the channel between the antenna array of the first network device andthe antenna array of the second network device according to the channelinformation of the N×M sub-channels that is from the receiving module.

Specifically, the sub-channel information of the N×M sub-channelsincludes a rank indicator RI and a precoding matrix indicator PMI.

Optionally, in another implementation manner, the apparatus for feedingback information about a channel between antenna arrays is furtherconfigured to perform the foregoing step 100. Referring to FIG. 4, theapparatus 200 further includes a sending module 230.

The sending module 230 is configured to send subarray configurationinformation to the second network device. The subarray configurationinformation is used to divide the antenna array of the first networkdevice into the M subarrays, and M is a positive integer greater than orequal to 2. Specifically, the subarray configuration information can besent by the sending module 230 by using a PDCCH, RLC signaling, or aPBCH.

For example, the subarray configuration information includes at leastone pattern, and the M subarrays of the antenna array of the firstnetwork device are determined according to the at least one pattern.

For example, the subarray configuration information includes a startport number of each subarray, and the M subarrays of the antenna arrayof the first network device are determined according to the start portnumber of each subarray.

Another example of the present disclosure provides an apparatus forfeeding back information about a channel between antenna arrays. Theapparatus is applied to a second network device and is configured toperform step 101 and step 102. Referring to FIG. 5, an apparatus 300 forfeeding back information about a channel between antenna arrays includesa processing module 310 and a sending module 320.

The processing module 310 is configured to generate channel informationof N×M sub-channels of a channel between an antenna array of a firstnetwork device and an antenna array of the second network device. Theantenna array of the first network device includes M subarrays. Theantenna array of the second network device includes N subarrays. M and Nare positive integers and are not both 1. The M subarrays and the Nsubarrays each include at least two antennas.

Specifically, the channel information of the N×M sub-channels betweenthe antenna array of the first network device and the antenna array ofthe second network device includes a rank indicator RI and a precodingmatrix indicator PMI. The processing module 310 can obtain the channelinformation of the N×M sub-channels in response to a reference signal(RS) from the first network device, or can obtain, based on channelreciprocity, the channel information of the N×M sub-channels.

The sending module 320 is configured to send the channel information ofthe N×M sub-channels to the first network device, so that the firstnetwork device generates channel information of the channel between theantenna array of the first network device and the antenna array of thesecond network device according to the channel information of the N×Msub-channels.

Optionally, in another implementation manner, referring to FIG. 5, theapparatus 300 for feeding back information about a channel betweenantenna arrays includes a receiving module 330.

The receiving module 330 is configured to receive subarray configurationinformation sent by the first network device. The subarray configurationinformation is used to divide the antenna array of the first networkdevice into the M subarrays, and M is a positive integer greater than 2.Specifically, the subarray configuration information can be received bythe receiving module 330 by using a PDCCH, or by receiving RLCsignaling, or by using a PBCH.

For example, the subarray configuration information includes at leastone pattern, and the M subarrays of the antenna array of the firstnetwork device are determined according to the at least one pattern.

For example, the subarray configuration information includes a startport number of each subarray, and the M subarrays of the antenna arrayof the first network device are determined according to the start portnumber of each subarray.

In addition, modules in the examples of the present disclosure may beintegrated into one processing module, or each of the modules may existalone physically, or two or more modules are integrated into one module.The integrated module may be implemented in a form of hardware, or maybe implemented in a form of a software function module. Steps of themethods disclosed with reference to the examples of the presentdisclosure may be directly executed and accomplished by using a hardwareencoding processor, or may be executed and accomplished by using acombination of hardware in the encoding processor and a software module.The software module may be located in a storage medium, such as a randomaccess memory, a flash memory, a read-only memory, a programmableread-only memory, an electrically erasable programmable memory, aregister, or the like.

If the modules or the integrated modules are implemented in the form ofhardware, the modules or the integrated modules may be integratedcircuits (ICs), application-specific integrated circuits (ASICs),field-programmable gate arrays (FPGAs), or the like, or may beintegrated into a baseband processor or a general-purpose processor.

When the modules or the integrated modules are implemented in the formof a software function module and are sold or used as independentproducts, the modules or the integrated modules may be stored in acomputer-readable storage medium. Based on such an understanding, thetechnical solutions of the present disclosure, or all or a part of thetechnical solutions may be implemented in a form of a software product.The software product is stored in a storage medium and includes severalinstructions for instructing a computer device (which may be a personalcomputer, a server, or a network device) to perform all or some of thesteps of the methods described in the examples of the presentdisclosure. The foregoing storage medium includes any medium that canstore program code, such as a USB flash drive, a removable hard disk, aread-only memory (ROM), a random access memory (RAM), a magnetic disk,or an optical disc.

The present disclosure may include dedicated hardware implementationssuch as application specific integrated circuits, programmable logicarrays and other hardware devices. The hardware implementations can beconstructed to implement one or more of the methods described herein.Applications that may include the apparatus and systems of variousexamples can broadly include a variety of electronic and computingsystems. One or more examples described herein may implement functionsusing two or more specific interconnected hardware modules or deviceswith related control and data signals that can be communicated betweenand through the modules, or as portions of an application-specificintegrated circuit. Accordingly, the computing system disclosed mayencompass software, firmware, and hardware implementations. The terms“module,” “sub-module,” “circuit,” “sub-circuit,” “circuitry,”“sub-circuitry,” “unit,” or “sub-unit” may include memory (shared,dedicated, or group) that stores code or instructions that can beexecuted by one or more processors.

The foregoing descriptions are merely specific examples of the presentdisclosure, but are not intended to limit the protection scope of thepresent disclosure. Any modification or replacement readily figured outby a person skilled in the art within the technical scope disclosed inthe present disclosure shall fall within the protection scope of thepresent disclosure. Therefore, the protection scope of the presentdisclosure shall be subject to the protection scope of the claims.

What is claimed is:
 1. A method for feeding back information about achannel between antenna arrays, comprising: receiving, by a firstnetwork device, sub-channel channel information of N×M sub-channels thatis sent by a second network device, wherein an antenna array of thefirst network device comprises M panels, an antenna array of the secondnetwork device comprises N panels, the channel between the first networkdevice and the second network device comprises the N×M sub-channels, Mis a positive integer that is greater than or equal to 2, N is apositive integer, M and N are not to be 1 at the same time, and the Mpanels and the N panels each comprise at least two antennas; andgenerating channel information of the channel between the first networkdevice and the second network device according to the sub-channelchannel information of the N×M sub-channels that is from the secondnetwork device.
 2. The method according to claim 1, wherein the methodfurther comprises: sending, by the first network device, subarrayconfiguration information to the second network device, wherein thesubarray configuration information indicates the antenna array of thefirst network device is divided into the M panels.
 3. The methodaccording to claim 2, wherein the subarray configuration informationcomprises a start port number of each panel, and each of the M panels isdetermined according to the start port number.
 4. The method accordingto claim 1, wherein the subarray configuration information comprises atleast one pattern, and the M panels are determined according to the atleast one pattern.
 5. The method according to claim 1, wherein N isequal to
 1. 6. The method according to claim 2, wherein the subarrayconfiguration information is sent by using a physical downlink controlchannel (PDCCH), radio link control (RLC) signaling, or a physicalbroadcast channel (PBCH).
 7. A method for feeding back information abouta channel between antenna arrays, comprising: generating, by a secondnetwork device, sub-channel channel information of N×M sub-channels ofthe channel between a first network device and the second networkdevice, wherein an antenna array of the first network device comprises Mpanels, an antenna array of the second network device comprises Npanels, M is a positive integer that is greater than or equal to 2, N ispositive integer, M and N are not to be 1 at the same time, and the Mpanels and the N panels each comprise at least two antennas; and sendingthe sub-channel channel information of the N×M sub-channels to the firstnetwork device, so that the first network device generates channelinformation of the channel between the first network device and thesecond network device according to the sub-channel channel informationof the N×M sub-channels.
 8. The method according to claim 7, wherein themethod further comprises: receiving, by the second network device,subarray configuration information sent by the first network device,wherein the subarray configuration information indicates the antennaarray of the first network device is divided into the M panels.
 9. Themethod according to claim 7, wherein the sub-channel channel informationof the N×M sub-channels comprises a rank indicator (RI) and a precodingmatrix indicator (PMI), each of the N×M sub-channels corresponds to onesub-channel matrix, and the sub-channel channel information of the N×Msub-channels is obtained according to the following steps: obtainingautocorrelation matrices of a N×M sub-channels matrices; and obtainingthe RI and the PMI of the N×M sub-channels according to theautocorrelation matrices of the N×M sub-channels matrices.
 10. Themethod according to claim 7, wherein the sub-channel channel informationof the N×M sub-channels comprises precoding in the form of a precodingmatrix, each of the N×M sub-channels corresponds to one sub-channelmatrix, and the generating, by the second network device, thesub-channel channel information of N×M sub-channels of the channelbetween the first network device and the second network devicecomprises: obtaining autocorrelation matrices of a N×M sub-channelsmatrices; and obtaining the precoding of the N×M sub-channels matricesaccording to the autocorrelation matrices of the channel matrices of theN×M sub-channels matrices.
 11. An apparatus for feeding back informationabout a channel between antenna arrays, comprising: a processor and anon-transitory computer-readable medium storing instructions that areexecutable by the processor, wherein the processor is configured to:receive sub-channel channel information of N×M sub-channels that is sentby a second network device, wherein an antenna array of a first networkdevice comprises M panels, an antenna array of the second network devicecomprises N panels, a channel between the second network device and thefirst network device comprises the N×M sub-channels, M is a positiveinteger that is greater than or equal to 2, N is positive integer, M andN are not to be 1 at the same time, and the M panels and the N panelseach comprise at least two antennas; and generate channel information ofthe channel between the first network device and the second networkdevice according to the received sub-channel channel information of theN×M sub-channels.
 12. The apparatus according to claim 11, wherein theprocessor is configured to: send subarray configuration information tothe second network device, the subarray configuration informationindicates the antenna array of the first network device is divided intothe M panels.
 13. The apparatus according to claim 12, wherein thesubarray configuration information comprises a start port number of eachpanel, and each of the M panels is determined according to the startport number.
 14. The apparatus according to claim 11, wherein thesubarray configuration information comprises at least one pattern, andthe M panels are determined according to the at least one pattern. 15.The apparatus according to claim 11, wherein N is equal to
 1. 16. Theapparatus according to claim 12, wherein the subarray configurationinformation is sent by using a physical downlink control channel(PDCCH), radio link control (RLC) signaling, or a physical broadcastchannel (PBCH).
 17. An apparatus for feeding back information about achannel between antenna arrays, comprising: a processor and anon-transitory computer-readable medium storing instructions that areexecutable by the processor, wherein the processor is configured to:generate sub-channel channel information of N×M sub-channels of thechannel between a first network device and a second network device,wherein an antenna array of the first network device comprises M panels,the antenna array of the second network device comprises N panels, M isa positive integer that is greater than or equal to 2, N is positiveinteger, M and N are not to be 1 at the same time, and the M panels andthe N panels each comprise at least two antennas; and send thesub-channel channel information of the N×M sub-channels to the firstnetwork device, so that the first network device generates channelinformation of the channel between the first network device and thesecond network device according to the sub-channel channel informationof the N×M sub-channels.
 18. The apparatus according to claim 17,wherein the processor is configured to: receive subarray configurationinformation sent by the first network device, wherein the subarrayconfiguration information indicates the antenna array of the firstnetwork device is divided into the M panels.
 19. The apparatus accordingto claim 17, wherein the sub-channel channel information of the N×Msub-channels comprises a rank indicator (RI) and a precoding matrixindicator (PMI), each of the N×M sub-channels corresponds to onesub-channel matrix, and the processor is further configured to: obtainautocorrelation matrices of a N×M sub-channels matrices; and obtain theRI and the PMI of the N×M sub-channels according to the autocorrelationmatrices of the N×M sub-channels matrices.
 20. The apparatus accordingto claim 17, wherein the sub-channel channel information comprises aprecoding in the form of a precoding matrix, each of the N×Msub-channels corresponds to one sub-channel matrix, and the processor isfurther configured to: obtain autocorrelation matrices of a N×Msub-channels matrices; and obtain the precoding of the N×M sub-channelsaccording to the autocorrelation matrices of the N×M sub-channelsmatrices.